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Org.eclipse.higgins.idas.udi

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This page describes the higgins.idas.udi component which implements UDI Resolution in Higgins. See http://www.azigo.com/company/dev/udi/ for details on UDIs.

A UDI is a string (URI, XRI, Linked Data URI or anything else) that somehow can be dereferenced to a Context, Entity or Attribute.

Javadoc

Service

Context UDIs

The following interfaces are provided to support the concept of Context UDIs:

/**
 * A Context UDI is an abstract, absolute pointer to an IdAS Context.
 */
public interface IContextUDI extends Serializable, Comparable {
 
	public IContextUDIMetadata getContextUDIMetadata();
}
 
/**
 * When you resolve a Context UDI, you get Context UDI Metadata.
 * This is:
 * - A list of one or more Context Types
 * - (optional) The type of Authentication Materials required to open the Context
 * - (optional) Configuration map for the Context
 */
public interface IContextUDIMetadata {
 
	public String[] getTypes() throws IdASException;
	public String[] getAuthNMaterialsTypes() throws IdASException;
	public String getAuthNMaterials() throws IdASException;
	public Map getConfiguration() throws IdASException;
}

Entity UDIs

The following interfaces are provided to support the concept of Entity UDIs:

/**
 * An Entity UDI is an abstract, absolute pointer to an IdAS Entity.
 */
public interface IEntityUDI extends Serializable, Comparable {
 
	public IEntityUDIMetadata getEntityUDIMetadata();
}
 
/**
 * When you resolve an Entity UDI, you get Entity UDI Metadata.
 * This is:
 * - Context UDI Metadata of the Context the Entity is in
 * - The Entity ID of the Entity
 */
public interface IEntityUDIMetadata {
 
	public IContextUDIMetadata getContextUDIMetadata() throws IdASException;
	public String getEntityID() throws IdASException;
}

Attribute UDIs

The following interfaces are provided to support the concept of Attribute UDIs:

/**
 * An Attribute UDI is an abstract, absolute pointer to an IdAS Attribute.
 */
public interface IAttributeUDI extends Serializable, Comparable {
 
	public IAttributeUDIMetadata getAttributeUDIMetadata();
}
 
/**
 * When you resolve an Attribute UDI, you get Attribbute UDI Metadata.
 * This is:
 * - Entity UDI Metadata of the Entity the Attribute belongs to
 * - The Attribute ID of the Attribute
 */
public interface IAttributeUDIMetadata {
 
	public IEntityUDIMetadata getEntityUDIMetadata() throws IdASException;
	public URI getAttributeID() throws IdASException;
}

UDIResolver

The UDIResolver is the central piece of the idas.udi project. It is a singleton class that you use to parse and resolve UDIs.

It is agnostic of any specific UDI implementation. Instead, it uses a list of IUDIFactory's (see next section) for parsing UDIs.

public class UDIResolver implements IConfigurableComponent {
 
	private static UDIResolver impl = null;
 
	private List udiFactoryList;
 
	public UDIResolver() {
 
		this.udiFactoryList = new ArrayList();
	}
 
	public static synchronized UDIResolver getInstance() {
 
		if (impl == null) impl = new UDIResolver();
		return(impl);
	}
 
	/**
	 * Register the IUDIFactorys from the configuration
	 */
	public void configure(Map mapGlobalSettings, String strComponentName, Map mapComponentSettings) throws Exception { ... }
 
	/**
	 * Parse a string into an IContextUDI by trying all registered IUDIFactorys
	 * until one succeeds.
	 */
	public IContextUDI parseContextUDI(String contextUDIStr) throws IdASException { ... }
 
	/**
	 * Parse a string into an IEntityUDI by trying all registered IUDIFactorys
	 * until one succeeds.
	 */
	public IEntityUDI parseEntityUDI(String entityUDIStr) throws IdASException { ... }
 
	/**
	 * Parse a string into an IAttributeUDI by trying all registered IUDIFactorys
	 * until one succeeds.
	 */
	public IAttributeUDI parseAttributeUDI(String attributeUDIStr) throws IdASException { ... }
 
	/**
	 * Resolve an IContextUDI to an IContext by retrieving the IContextUDIMetadata
	 */
	public IContext resolve(IContextUDI contextUDI, Object authentication) throws IdASException { ... }
 
	/**
	 * Resolve an IEntityUDI to an IEntity by retrieving the IEntityUDIMetadata
	 */
	public IEntity resolve(IEntityUDI entityUDI, Object authentication) throws IdASException { ... }
 
	/**
	 * Resolve an IAttributeUDI to an IAttribute by retrieving the IAttributeUDIMetadata
	 */
	public IAttribute resolve(IAttributeUDI attributeUDI, Object authentication) throws IdASException { ... }
}

IUDIFactory

A UDI Factory is one specific implementation of the generic UDI concept. It can parse strings into IContextUDIs, IEntityUDIs and IAttributeUDIs. The UDIResolver singleton class keeps a list of IUDIFactory's. This list can be configured via the Configuration API.

The IUDIFactory interface is simple:

public interface IUDIFactory {
 
	public IContextUDI parseContextUDI(String contextUDI);
	public IEntityUDI parseEntityUDI(String entityUDI);
	public IAttributeUDI parseAttributeUDI(String attributeUDI);
}

The following IUDIFactory implementations are included in Higgins:

  • XDIUDIFactory: Can parse XRIs into Context UDIs, Entity UDIs and Attribute UDIs.
  • URIUDIFactory: Can parse URIs without fragments into Context UDIs and Entity UDIs.
  • HashURIUDIFactory: Can parse URIs with fragments into Context UDIs and Entity UDIs.
  • ConfUDIFactory: This makes it possible to also use the Context IDs stored in IdASRegistry as Context UDIs.
  • PDSUDIFactory: Can parse sync:// UDIs to enable the Personal Data Store.

Because of this configurable IUDIFactory mechanism, the UDI concept is extensible. New kinds of UDIs (pointers to Contexts, Entities and Attributes) can be realized by simply writing another IUDIFactory implementation.

The following is an example configuration XML file for UDIResolver that shows a possible default list of IUDIFactory's:

<Configuration
	xmlns:xsd="http://www.w3.org/2001/XMLSchema"
	xmlns="http://higgins.eclipse.org/Configuration"
	xmlns:htf="http://higgins.eclipse.org/Configuration"
	xsd:schemaLocation="http://higgins.eclipse.org/Configuration Configuration.xsd">
 
	<!--  The setting handlers are classes that consume Setting elements where the Type matches and generate an object of the Class -->
	<SettingHandlers>
		<SettingHandler Type="htf:map" Class="java.util.Map" Handler="org.eclipse.higgins.configuration.xml.MapHandler"/>
		<SettingHandler Type="htf:list" Class="java.util.List" Handler="org.eclipse.higgins.configuration.xml.ListHandler"/>
		<SettingHandler Type="htf:string" Class="java.lang.String" Handler="org.eclipse.higgins.configuration.xml.StringHandler"/>
		<SettingHandler Type="htf:boolean" Class="java.lang.Boolean" Handler="org.eclipse.higgins.configuration.xml.BooleanHandler"/>
		<SettingHandler Type="htf:classsingleton" Class="java.lang.Object" Handler="org.eclipse.higgins.configuration.xml.ClassSingletonHandler"/>
		<SettingHandler Type="htf:classinstance" Class="java.lang.Object" Handler="org.eclipse.higgins.configuration.xml.ClassInstanceHandler"/>
	</SettingHandlers>
 
	<Setting Name="DeploymentConfiguration" Type="htf:map">
 
		<Setting Name="ComponentSettings" Type="htf:map">
 
			<Setting Name="XRIUDIFactory" Type="htf:map">
				<Setting Name="Resolver" Type="htf:map">
					<Setting Name="MaxFollowRedirects" Type="htf:string">5</Setting>
					<Setting Name="MaxFollowRefs" Type="htf:string">10</Setting>
					<Setting Name="MaxRequests" Type="htf:string">15</Setting>
					<Setting Name="MaxTotalBytes" Type="htf:string">10485760</Setting>
					<Setting Name="MaxBytesPerRequest" Type="htf:string">1048576</Setting>
					<Setting Name="AtAuthority" Type="htf:string"><![CDATA[<XRD xmlns="xri://$xrd*($v*2.0)" xmlns:xrd="xri://$xrd*($v*2.0)"><Status cid="verified" ceid="off" code="100" /><CanonicalID>@</CanonicalID><Service><Type>xri://$res*auth*($v*2.0)</Type><MediaType match="default" select="false" /><URI priority="1">https://at.xri.net/</URI><URI priority="2">http://at.xri.net/</URI></Service> </XRD>]]></Setting>
					<Setting Name="EqualsAuthority" Type="htf:string"><![CDATA[<XRD xmlns="xri://$xrd*($v*2.0)" xmlns:xrd="xri://$xrd*($v*2.0)"><Status cid="verified" ceid="off" code="100" /><CanonicalID>=</CanonicalID><Service><Type>xri://$res*auth*($v*2.0)</Type><MediaType match="default" select="false" /><URI priority="1">https://equal.xri.net/</URI><URI priority="2">http://equal.xri.net/</URI></Service> </XRD>]]></Setting>
					<Setting Name="BangAuthority" Type="htf:string"><![CDATA[<XRD xmlns="xri://$xrd*($v*2.0)" xmlns:xrd="xri://$xrd*($v*2.0)"><Status cid="verified" ceid="off" code="100" /><CanonicalID>!</CanonicalID><Service><Type>xri://$res*auth*($v*2.0)</Type><MediaType match="default" select="false" /><URI priority="1">https://bang.xri.net/</URI><URI priority="2">http://bang.xri.net/</URI></Service> </XRD>]]></Setting>
				</Setting>
				<Setting Name="ResolverFlags" Type="htf:map">
					<Setting Name="https" Type="htf:boolean">false</Setting>
					<Setting Name="saml" Type="htf:boolean">false</Setting>
					<Setting Name="cid" Type="htf:boolean">true</Setting>
					<Setting Name="refs" Type="htf:boolean">true</Setting>
				</Setting>
			</Setting>
			<Setting Name="URIUDIFactory" Type="htf:map" />
			<Setting Name="HashURIUDIFactory" Type="htf:map" />
			<Setting Name="ConfUDIFactory" Type="htf:map" />
 
			<Setting Name="UDIResolver" Type="htf:map">
				<Setting Name="UDIFactoryInstancesList" Type="htf:list">
					<Setting Name="XRIUDIFactory" Type="htf:string">XRIUDIFactory</Setting>
					<Setting Name="URIUDIFactory" Type="htf:string">URIUDIFactory</Setting>
					<Setting Name="HashURIUDIFactory" Type="htf:string">HashURIUDIFactory</Setting>
					<Setting Name="ConfUDIFactory" Type="htf:string">ConfUDIFactory</Setting>
				</Setting>
			</Setting>
 
			<Setting Name="IdASRegistry" Type="htf:map">
				<Setting Name="ContextFactoryInstancesList" Type="htf:list">
					<Setting Name="JNDIContextFactory" Type="htf:map">
						<Setting Name="Instance" Type="htf:string">JNDIContextFactory</Setting>
						<Setting Name="ContextTypes" Type="htf:list">
							<Setting Name="ContextType1" Type="htf:string">($context)*(+ldap)</Setting>
						</Setting>
					</Setting>
					<Setting Name="RDFContextFactory" Type="htf:map">
						<Setting Name="Instance" Type="htf:string">RDFContextFactory</Setting>
						<Setting Name="ContextTypes" Type="htf:list">
							<Setting Name="ContextType1" Type="htf:string">$context$mime*application*rdf.xml</Setting>
						</Setting>
					</Setting>
				</Setting>
 
				<Setting Name="ContextIdsList" Type="htf:list">
					<Setting Name="localContext" Type="htf:map">
						<Setting Name="ContextId" Type="htf:string">localContext</Setting>
						<Setting Name="ContextTypes" Type="htf:list">
							<Setting Name="HigginsContextType" Type="htf:string">$context+ldap</Setting>
						</Setting>
						<Setting Name="Connection" Type="htf:map">
							<Setting Name="ConnectionType" Type="htf:string">LDAP</Setting>
							<Setting Name="AddressList" Type="htf:list">
								<Setting Name="Address" Type="htf:string">ldap://rh158.sohosmart.net:7389</Setting>
							</Setting>
							<Setting Name="jndiProvider" Type="htf:string">com.sun.jndi.ldap.LdapCtxFactory</Setting>
						</Setting>
						<Setting Name="env" Type="htf:map">
							<Setting Name="java.naming.security.authentication" Type="htf:string">simple</Setting>
						</Setting>
					</Setting>
				</Setting>
 
			</Setting>
 
		</Setting>
 
		<Setting Name="XRIUDIFactory" Type="htf:classinstance">org.eclipse.higgins.idas.udi.impl.xri.XRIUDIFactory</Setting>
		<Setting Name="URIUDIFactory" Type="htf:classinstance">org.eclipse.higgins.idas.udi.impl.uri.URIUDIFactory</Setting>
		<Setting Name="HashURIUDIFactory" Type="htf:classinstance">org.eclipse.higgins.idas.udi.impl.hashuri.HashURIUDIFactory</Setting>
		<Setting Name="ConfUDIFactory" Type="htf:classinstance">org.eclipse.higgins.idas.udi.impl.conf.ConfUDIFactory</Setting>
 
		<Setting Name="UDIResolver" Type="htf:classsingleton">org.eclipse.higgins.idas.udi.UDIResolver</Setting>
 
		<Setting Name="JNDIContextFactory" Type="htf:classinstance">org.eclipse.higgins.idas.cp.jndi.JNDIContextFactory</Setting>
		<Setting Name="RDFContextFactory" Type="htf:classinstance">org.eclipse.higgins.idas.cp.rdf.RDFContextFactory</Setting>
 
		<Setting Name="IdASRegistry" Type="htf:classsingleton">org.eclipse.higgins.idas.registry.IdASRegistry</Setting>
 
	</Setting>
 
</Configuration>

Example usage

Here is some example code that contains three examples of how you can start with an Entity UDI and end up with a fully instantiated Entity:

import org.eclipse.higgins.configuration.xml.ConfigurationHandler;
import org.eclipse.higgins.idas.api.IEntity;
import org.eclipse.higgins.idas.udi.IEntityUDI;
import org.eclipse.higgins.idas.udi.UDIResolver;
 
ConfigurationHandler handler = new ConfigurationHandler();
 
handler.setConfigurationBase(".");
handler.setFileName("test.xml");
handler.configure(null);
 
UDIResolver resolver = (UDIResolver) handler.getSettings().get("UDIResolver");
 
// Example 1: Entity UDI in XRI form
 
IEntityUDI entityUDI1 = resolver.parseEntityUDI("@parity*contexts/($context)*(+ldap)*(+poc)//uid%3Dmarkus,ou%3Didentities,dc%3Dhiggins,dc%3Declipse,dc%3Dorg");
Object authnMaterials1 = /* ... */;
 
IEntity entity1 = resolver.resolve(entityUDI1, authnMaterials1);
 
// Example 2: Entity UDI in URI form (Linked Data "303" Cool URI):
 
IEntityUDI entityUDI2 = resolver.parseEntityUDI("http://www.acme.com/id/alice");
Object authnMaterials2 = /* ... */;
 
IEntity entity2 = resolver.resolve(entityUDI2, authnMaterials2);
 
// Example 3: Entity UDI using a Context from the local Configuration file
 
IEntityUDI entityUDI3 = resolver.parseEntityUDI("localContext/uid=markus,ou=identities,dc=higgins,dc=eclipse,dc=org");
Object authnMaterials2 = /* ... */;
 
IEntity entity3 = resolver.resolve(entityUDI3, authnMaterials3);

The only difference between the examples is that different IUDIFactory implementations are used internally by the UDIResolver.

Q&A

  • Why are there separate IxxxUDI and IxxxUDIMetadata interfaces? Why isn't it enough to have IxxxUDI?

The IxxxUDI interface represents the UDI itself. The IxxxUDIMetadata interface provides all the information needed to instantiate the object the UDI points to. The reason why the two interfaces are separate is that an Entity UDI (IEntityUDI) does NOT necessarily have to contain within itself a Context UDI, but it DOES have to provide Context UDI Metadata for the Context the Entity is in. Similarly, an Attribute UDI (IAttributeUDI) does NOT necessarily have to contain within itself an Entity UDI, but it DOES have to provide Entity UDI Metadata for the Entity the Attribute belongs to.

The current idea is that Context IDs from the Configuration API are considered one flavor of Context UDIs, i.e. you are able to parse and resolve them with the UDIResolver class. However, the idas.udi project is not required, if all you need is read/write Context IDs in your configuration file.

Relation to IdASRegistry

IdAS UDI Resolution is a way of discovering Contexts, Entities and Attributes from a UDI. It uses IdASRegistry to look up a suitable Context Provider based on the discovered Context Types.

Therefore, idas.udi depends on idas.registry. The converse is not true, i.e. idas.registry does not depend on idas.udi.

See Also